This invention relates to a coreless surface winder and method and, more particularly to a winder that does not use a core or mandrel but which produces a solid roll, i.e., there is no hole in the center with the resulting retail-size roll being "coreless". As such, the product is considered "environmentally friendly" in that there is less packaging material required and no core to dispose of.
Surface winders operate on the exterior of the paper being wound into a log and usually employ a three drum or roller cradle for this purpose--see, for example, co-owned U.S. Pat. No. 4,828,195. The three rollers usually include first and second winding rollers and a pivotally mounted rider roller. Historically, a core is introduced into the nip between the two winding rollers where it becomes enveloped with the web being wound--with the wind being completed when the incipient log is cradled among the three rollers. The log generally is of a length to provide a plurality of retail size rolls--each being about 4" (100 mm) to 5" (125 mm) length. These logs are continuously wound at high speed generally 2500-3000 fpm (750-900 mpm) resulting in 20-30 logs per minute having axial lengths of from about 100" (3 m) to about 200" (6 m).
According to the invention, there is no core and the wind is started by a rubbing motion brought about by introducing a folded leading edge of a severed web into the space between a bedroll-type winding drum and an arcuate, relatively elongated dead plate mounted in radially movable relation to the winding drum. At the speeds involved, it is only a fraction of a second for the leading edge to form an incipient roll or log and travel to the end of the dead plate (which extends only about a portion of the drum) and exit into the conventional three roller cradle.
Immediately after the incipient log passes the narrowest point, the dead plate is moved away from the drum to avoid accidental rubbing on the web but this movement is small, of the order of 0.01-0.10 inches and in the very short time mentioned above. To accommodate the buildup of convolutely wound layers, the deadplate contoured diverges slightly from the winding drum to provide increasing clearance as the new log progresses around the drum.
The phenomenon of a reverse folded leading edge is illustrated in detail in co-owned patent U.S. Pat. No. Re. 28,353. There, a portion of the web rearward of a severed leading edge is immobilized against the surface of a bedroll. When that occurs, windage and centrifugal force curl the leading edge on itself back to the immobilizing means which may be vacuum, pins, etc. In the '353 patent at transfer, pushers engaged the folded leading edge against the glue-equipped cores. The reverse fold was important to ensure the control of the leading edge by entrapping the two plies during the adhesion process. The advantage of the folded web, as described in the '353 patent, is the entrapment of the other ply when two ply tissue is being wound. If the leading edge was not controlled, it could fly away under the influence to the above mentioned factors: windage and centrifugal force. This would stop the winding.
The advantage of the folded web in the instant invention is to increase its width by at least two thicknesses, making it wide enough to cause the leading edge of the web to roll back onto itself as it enters the converging passage. So, it is clear that the operation of prior art winders is completely different from that of the instant invention. Hence, we have found another advantageous use of the reversely folded leading edge portion so as to be able to start a surface wind and thereby provide a solid roll.
Other objects, advantages and details of the instant invention may be seen in the ensuing specification.